Two frequencies can be mixed to produce the sum and the difference in a heterodyne process. A super-heterodyne receiver mixes a high frequency input signal with a local frequency generated in a receiver to produce a signal at a frequency that is the difference between the frequency of the input signal and the local frequency generated in the receiver. The produced signal is typically designed to be at a pre-determined frequency, called the intermediate frequency (IF) so that the signal at a high input frequency can be down converted for process at the pre-determined intermediate frequency (IF). The local frequency can be adjusted so that the signal received in the desired channel of frequency can be down converted to the intermediate frequency (IF) for selection and for further processing at the fixed intermediate frequency.
Typically, a television tuner module uses one or more integrated circuits and a number of discrete components, such as low noise amplifiers, mounted on a printed circuit board.
Bud Taddiken, et al. presented a broadband tuner on a chip in 2000 IEEE Radio Frequency Integrated Circuits Symposium, “Broadband Tuner on a chip for cable modem, HDTV, and legacy analog standards (Invited),” pp. 17-20, 2000. In the broadband tuner of Bud Taddiken, et al., the chip was implemented using a silicon BiCMOS process. The low noise amplifier (LNA) in the chip of Bud Taddiken, et al. uses bipolar transistor.
There are two major categories of transistors: bipolar and field effect transistors (FET). FET-based silicon chips are easier to construct than their bipolar counterparts. FETs typically switch slower than bipolar transistors, but use less power.
Metal oxide semiconductor FETs (MOSFETs) includes n-channel based NMOS and p-channel based PMOS. On a chip, NMOS and PMOS transistors can be constructed together in a complementary fashion to create complementary metal oxide semiconductor (CMOS) gates, which consume significantly less power than their bipolar equivalents. A CMOS gate consumes almost no power until the transistors switch.
Bipolar junction transistors (BJTs) are typically used for high power applications and high radio frequency (RF) applications that reach into the gigahertz range. Bipolar transistors are available as individually packaged discrete components as well as on an integrated circuit chip. BiCMOS is type of integrated circuit that uses both bipolar and CMOS technologies.
For convenience, in the present description, it is understood that a BiCMOS chip is not considered as a CMOS chip.
Mark Dawkins, et al. presented a single-chip turner for digital terrestrial television, using a bipolar technology, in “A single-chip tuner for DVB-T,” IEEE Journal of Solid-State Circuits, Vol. 38, No. 8, August 2003.